Change datetime.now() to dt_util.now() (#26582)

* Change datetime.now() to dt_util.now() in cases where the functionality should stay the same

These changes should not affect the functionality, rather cleanup our codebase.

In general we would like integrations to not to use datetime.now() unless there's a very good
reason for it, rather use our own dt_util.now() which makes the code aware of our current time
zone.

* Use datetime.utcnow() for season sensor to get offset-naive utc time

* Revert "Use datetime.utcnow() for season sensor to get offset-naive utc time"

This reverts commit 5f36463d9c7d52f8e11ffcec7e57dfbc7b21bdd1.

* BOM sensor last_updated should be UTC as well

* Run black

* Remove unused last_partition_update variable

homeassistant/components/ring/switch.py

@@ -1,9 +1,10 @@
 """This component provides HA switch support for Ring Door Bell/Chimes."""
 import logging
-from datetime import datetime, timedelta
+from datetime import timedelta
 from homeassistant.components.switch import SwitchDevice
 from homeassistant.helpers.dispatcher import async_dispatcher_connect
 from homeassistant.core import callback
+import homeassistant.util.dt as dt_util
 
 from . import DATA_RING_STICKUP_CAMS, SIGNAL_UPDATE_RING
 
@@ -72,14 +73,14 @@ class SirenSwitch(BaseRingSwitch):
     def __init__(self, device):
         """Initialize the switch for a device with a siren."""
         super().__init__(device, "siren")
-        self._no_updates_until = datetime.now()
+        self._no_updates_until = dt_util.utcnow()
         self._siren_on = False
 
     def _set_switch(self, new_state):
         """Update switch state, and causes HASS to correctly update."""
         self._device.siren = new_state
         self._siren_on = new_state > 0
-        self._no_updates_until = datetime.now() + SKIP_UPDATES_DELAY
+        self._no_updates_until = dt_util.utcnow() + SKIP_UPDATES_DELAY
         self.schedule_update_ha_state()
 
     @property
@@ -102,7 +103,7 @@ class SirenSwitch(BaseRingSwitch):
 
     def update(self):
         """Update state of the siren."""
-        if self._no_updates_until > datetime.now():
+        if self._no_updates_until > dt_util.utcnow():
             _LOGGER.debug("Skipping update...")
             return
         self._siren_on = self._device.siren > 0